How do you answer Describe a successful project you worked on and how you contributed to that success?

You must analyze the question to determine what is required. This question appears to be designed to illicit an aspect of your previous job experience and how aptly you performed as a team member. For example, here is a hypothetical answer:

"I was a member of a four man team tasked with counting all the inventory in the hardware store where I worked. By dividing the tasks between us, we were able to inventory over five thousand items of stock in five working days. We were able to accomplish this task efficiently partially due to the computer program I wrote to catalogue each group of items within their respective locations in the storeroom."